This invention relates generally to apparatus for pumping liquid metal and more particularly to an electric pump for pumping liquid metals to high pressures in high temperature environments without the use of magnets or moving mechanical parts.
Pumps for liquid metals are generally known and include not only electromagnetic and mechanical pumps, but also pumps of the type whereby the metal is electrolyzed through a liquid electrolyte barrier.
While electromagnetic pumps include simplicity, the lack of moving parts, and a moderate pressure and temperature capability, mechanical pumps normally have a relatively high pressure capability and high efficiency. However, neither of these types of pumps is capable of both high pressure and high temperature operation. The electromagnetic pump is limited to moderate pressures by the practical magnitudes of electrical current and magnetic-field strength. It is further limited in temperature by the materials used to produce the magnetic field. The magnetic circuit also imposes severe weight penalties. Typical examples of electromagnetic pumps include those shown and described in: U.S. Pat. No. 3,885,890, "Electromagnetic Pumps", Davidson, and U.S. Pat. No. 4,765,948, "Coolant Circulation System For A Liquid Metal Nuclear Reactor", DeLuca et al. Mechanical pumps driven by electric motors are also subject to temperature limits and weight penalties imposed by the motor.
Where liquid metals are electrolyzed through a liquid electrolyte barrier, pumping pressure is limited to the small hydrostatic pressure that naturally occurs across the electrolyte. Examples of the liquid electrolyte type pump include U.S. Pat. No. 3,591,312, Liquid Mercury Flow Control and "Measuring System", Eckhardt and U.S. Pat. No. 3,600,104, "Method And Apparatus For Controlled Pumping Of Liquid Mercury", King.